1. Field of the Invention
The present invention relates to vehicle wheel bearing assemblies and more particularly to such assemblies equipped with sensing arrangements for sensing rotary speed or position.
In this field there have been many prior art constructions which can be taken to form the background for the invention. In general, rotary bearings employing sensing arrangements for sensing rotary speed or position can employ a pre-fabricated annular component made of polymeric material containing ferrous material which is treated to form alternate north and south magnetic poles, see for example, U.S. Pat. No. 5,089,817. Such a component referred to as an encoder can be mounted in the assembly to cause the magnetic poles to pass alongside a sensor, such as a Hall effect sensor, which generates a pulsed electrical signal.
2. Description of the Prior Art
An object of the present invention is to provide improved assemblies and sensing arrangements of the aforementioned kind.
Accordingly the present invention provides a wheel bearing assembly composed of inner and outer bearing rings, one of which is intended to rotate and the other of which is intended to remain stationary, two sets of rolling elements between the rings and in angular contact with tracks defined by the rings, each set of rolling elements being spaced in the direction of the axis of rotation with each set of rolling elements retained by one of two cages and a sensing arrangement composed of at least two annular encoders with alternate north and south magnetic poles and at least two sensors operably associated with the encoders and each serving to provide electrical signals generated by the passage of the poles of the associated encoder; wherein one of the encoders is mounted on the rotatable one of the bearing rings and, the other of the encoders is mounted on one of the cages and each of said sensors and encoders is disposed axially, between the sets of rolling elements.
The encoder can be mounted on different components of the assembly such as on one of the cages and on the rotatable bearing ring. This enables the signals generated by the sensors to be compared, for example. The encoders can be orientated with their magnetic poles parallel to the rotational axis thus in an axial orientation or radial to this axis thus in a radial orientation or in both axial and radial orientations. The sensors and encoders may be built into the bearing in a protected position between the sets of rolling elements. To locate the sensors use can be made of a housing or a mounting as described hereinafter.
In other embodiments the sensors and encoders lie outboard of the bearing and the wheel assembly for ease of installation or removal.
A second aspect of the present invention provides a wheel bearing assembly composed of inner and outer bearing rings, one of which is intended to rotate and the other of which is intended to remain stationary, sets of rolling elements between the rings and in angular contact with tracks defined by the rings, the sets of rolling elements being spaced in the direction of the axis of rotation with each set of rolling elements retained by a cage and a sensing arrangement composed of at least two annular encoders with alternate north and south magnetic poles and at least two sensors operably associated with the encoders and each serving to provide electrical signals generated by the passage of the poles of the associated encoder; wherein one of the encoders is mounted on the rotatable one of the bearing rings and, the other of the encoders is mounted on one of the cages and wherein the inner bearing ring is secured onto a wheel hub, a cover is located on the other bearing ring to enclose the sensors and is carried by an axial portion of the cover.
The invention may be understood more readily, and various other aspects and features of the invention may become apparent, from consideration of the following description.